1. Field of the Invention
The invention relates to communications systems generally, and more particularly to telephony systems in which a request for a call to a device can be made.
2. Discussion of the Background
The use of the Internet to conduct transactions has become increasingly popular over the last several years. One use of the Internet has been the implementation of callback systems. In general, an Internet callback system allows a user who visits a website to request that some entity associated with the website initiate a call to the user. This call may be a call that is made via user's computer using a VoIP application, but is more commonly a PSTN (public switched telephone network) call made to a PSTN telephone number provided by the user.
A callback service is useful in many different situations, including, but not limited to, e-commerce. For example, the assignee of the present invention, eStara Corp., provides a Push-to-Talk™ service that contains a component known as Phone2Phone™ which allows a user to enter their telephone number into a web page. The eStara Phone2Phone™ service will then automatically place a PSTN call to the telephone number specified by the user and to the web site owner's call center, and then bridge the two calls together to establish a PSTN connection between the user and the retailer. Callback systems can also be implemented with one or both portions of the call employing VoIP technology.
A problem with allowing the user to specify a device (either a PSTN extension or a URL different from the URL from which the user is making the callback request) to which the call is to be made is that it is difficult to verify the authenticity of the data, and users can enter bogus data. This can lead to unwanted calls, e.g., crank calls, where a malicious user makes multiple callback requests for calls to a party who does not desire such calls. Alternatively, a malicious user may harass a particular retailer by making single callback requests for callbacks to devices (e.g., different PSTN extensions or different URLs) corresponding to different requesting parties from the same retailer.
In the past, eStara has used a manual procedure to develop a blacklist to help prevent such calls. In this manual procedure, when a called party recognizes that a received call has not been requested by the calling party, the called party can add the calling party's number to eStara's blacklist by visiting the eStara website and/or sending an email identifying the number to which the unwanted callback was requested (this number is provided to the retailer to allow operation of screen pops of customer-specific information as described in co-pending U.S. patent application Ser. No. 09/771,993 filed Jan. 30, 2001, assigned to eStara, Inc.) This method has the drawback of requiring a manual operation on the part of the called party. Additionally, it is not effective against a malicious user who harasses a particular retailer by making multiple callback requests from different parties to the same retailer.
What is needed is an automated method for preventing unwanted calls that can prevent attacks by malicious users who make multiple callback requests for different user devices.